General plant compressed air quality requirements are mainly focused on oil content, dust content and dryness the standards vary across industries and application scenarios, but generally follow the following norms:
1. oil content requirements
- general Standard: Most industrial scenarios require the oil content of compressed air to be less than or equal to 0.1 mg/m & sup3; to avoid oil pollution to the environment, affecting product quality or damaging seals. This standard is achieved by conventional monitoring methods such as color reaction tubes, and its detection limit can reach 0.1 mg/m & sup3;.
- High precision standard: In food, pharmaceutical, electronic and other industries that have strict requirements on the oil content of compressed air, it is necessary to reach Class 0 in ISO 8573-1 standard, I .e. oil content ≤ 0.01 mg/m & sup3;. This standard uses ISO 8573 partial flow (b2) or full flow (b1) methods to test foggy oil, liquid oil, and gaseous oil to ensure that the compressed air is almost free of oil.
2. dust content requirements
- particle size the particle size of the particles in the compressed air should generally be less than or equal to a certain value, such as less than 1μm, to avoid dust and other impurities affecting the quality of the product.
- concentration of particulate matter: Different industries have different requirements for particulate matter concentration. For example, the production of electronic components has extremely high environmental requirements, and the content of particulate matter in compressed air should be very low. Generally, the particle size is less than 0.1 μm to avoid damage to electronic components or affect their performance.
3. dryness requirement
dew point temperature: The dryness of compressed air is usually expressed by dew point temperature. The lower the dew point temperature, the drier the air. Different industrial scenarios have very different dew point requirements, for example:
- semiconductor, aerospace and other high-precision industries dew point ≤-70 ℃ is required to ensure an extremely dry environment.
- Food packaging, pharmaceutical workshop dew point ≤-40 ℃ is required to prevent water pollution to the product.
- Pneumatic tools, automated production lines dew point ≤-20 ℃ is required to meet the general industrial needs.
- Not demanding environment for dryness: Dew point temperature may be relaxed to ≤ 10 ℃.
Moisture content: The moisture content in the compressed air needs to be strictly controlled to prevent condensation into water in the system, causing components to rust, freeze or affect the control accuracy. For example, in the production of pharmaceuticals, a dew point not exceeding -20°C should meet the needs of most pharmaceuticals, taking into account the possible corrosivity of moisture to gas transmission pipelines.
4. other requirements
- pressure stability: The working pressure of compressed air should be kept stable within the specified range to avoid excessive pressure fluctuations affecting the working performance of the system.
- temperature suitability: The temperature of the compressed air should not be too high or too low to prevent damage to the components or affect the air properties.
- Microbial limit in certain industries (e. g. pharmaceutical, food), the microbial limit of compressed air also needs to be strictly controlled to prevent microbial contamination of products. For example, compressed air entering the aseptic area should be sterile filtered to at least the microbial limit level of Class A laminar air, I .e. less than 1 CFU/m & sup3;.
